# Highly Sensitive Electrochemiluminescence Analysis of miRNA-107 Using AIE-Active Polymer Dots as Emitters

## TL;DR

A new electrochemiluminescence sensor was developed to detect miRNA-107 with high sensitivity, using polymer dots and a signal 'on-off' mechanism triggered by RNA-DNA interactions.

## Contribution

A novel AIECL-based biosensor platform for ultrasensitive miRNA-107 detection with a low detection limit.

## Key findings

- The biosensor detected miRNA-107 with a detection limit as low as 0.82 fM.
- The sensor exhibited a wide linear response range from 1.0 fM to 10.0 pM of miRNA-107.
- The ECL signal recovery was achieved through RNA-DNA hybridization and nuclease cleavage.

## Abstract

The ultrasensitive detection of microRNA-17 (miRNA-107) is required for clinical diagnosis. In this work, an aggregation-induced electrochemiluminescence (AIECL) sensor was developed for the quantification of miRNA-107, in which AIECL-active polymer dots (Pdots) were characterized by transmission electron microscopy, ultraviolet–visible spectroscopy, and cyclic voltammetry and used as ECL emitters. Black hole quencher-labeled hairpin DNA (HP-BHQ) was modified on the Pdot surfaces, resulting in the ECL signal of the Pdots being in the “off” state due to the resonant energy transfer (RET) between the BHQ and Pdots. In the presence of miRNA-107, HP-BHQ opened through RNA-DNA hybridization. Subsequently, the introduced duplex-specific nuclease (DSN) facilitated the cleavage of DNA in the RNA–DNA hybrid chain and led to the detachment of HP-BHQ from the electrode surface. The ECL signal of the Pdots recovered, i.e., to the “on” state. The variation in the ECL signal was related to the concentration of the target miRNA-107. As a result, the AIECL biosensor exhibited a wide linear response to miRNA-107 concentrations ranging from 1.0 fM to 10.0 pM, and a low detection limit of 0.82 fM. This work provides a novel platform for the sensitive analysis of miRNA.